EC - 16S rRNA (guanine1405-N7)-methyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
16S rRNA (guanine1405-N7)-methyltransferase
Other names:
methyltransferase Sgm
m7G1405 Mtase
Sgm Mtase
sisomicin-gentamicin methyltransferase
sisomicin-gentamicin methylase
Systematic name:
S-adenosyl-L-methionine:16S rRNA (guanine1405-N7)-methyltransferase



The enzyme from the antibiotic-producing bacterium Micromonospora zionensisspecifically methylates guanine1405 at N7 in 16S rRNA, thereby rendering the ribosome resistant to 4,6-disubstituted deoxystreptamine aminoglycosides, which include gentamicins and kanamycins [2].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Husain, N., Tkaczuk, K. L., Tulsidas, S. R., Kaminska, K. H., Cubrilo, S., Maravic-Vlahovicek, G., Bujnicki, J. M., Sivaraman, J.
    Structural basis for the methylation of G1405 in 16S rRNA by aminoglycoside resistance methyltransferase Sgm from an antibiotic producer: a diversity of active sites in m7G methyltransferases.
    Nucleic Acids Res. 38 : 4120-4132 (2010). [PMID: 20194115]
  2. Savic, M., Lovric, J., Tomic, T. I., Vasiljevic, B., Conn, G. L.
    Determination of the target nucleosides for members of two families of 16S rRNA methyltransferases that confer resistance to partially overlapping groups of aminoglycoside antibiotics.
    Nucleic Acids Res. 37 : 5420-5431 (2009). [PMID: 19589804]
  3. Tomic, T. I., Moric, I., Conn, G. L., Vasiljevic, B.
    Aminoglycoside resistance genes sgm and kgmB protect bacterial but not yeast small ribosomal subunits in vitro despite high conservation of the rRNA A-site.
    Res. Microbiol. 159 : 658-662 (2008). [PMID: 18930134]
  4. Savic, M., Ilic-Tomic, T., Macmaster, R., Vasiljevic, B., Conn, G. L.
    Critical residues for cofactor binding and catalytic activity in the aminoglycoside resistance methyltransferase Sgm.
    J. Bacteriol. 190 : 5855-5861 (2008). [PMID: 18586937]
  5. Maravic Vlahovicek, G., Cubrilo, S., Tkaczuk, K. L., Bujnicki, J. M.
    Modeling and experimental analyses reveal a two-domain structure and amino acids important for the activity of aminoglycoside resistance methyltransferase Sgm.
    Biochim. Biophys. Acta 1784 : 582-590 (2008). [PMID: 18343347]
  6. Kojic, M., Topisirovic, L., Vasiljevic, B.
    Cloning and characterization of an aminoglycoside resistance determinant from Micromonospora zionensis.
    J. Bacteriol. 174 : 7868-7872 (1992). [PMID: 1447159]
  7. Schmitt, E., Galimand, M., Panvert, M., Courvalin, P., Mechulam, Y.
    Structural bases for 16 S rRNA methylation catalyzed by ArmA and RmtB methyltransferases.
    J. Mol. Biol. 388 : 570-582 (2009). [PMID: 19303884]
  8. Wachino, J., Shibayama, K., Kimura, K., Yamane, K., Suzuki, S., Arakawa, Y.
    RmtC introduces G1405 methylation in 16S rRNA and confers high-level aminoglycoside resistance on Gram-positive microorganisms.
    FEMS Microbiol. Lett. 311 : 56-60 (2010). [PMID: 20722735]
  9. Liou, G. F., Yoshizawa, S., Courvalin, P., Galimand, M.
    Aminoglycoside resistance by ArmA-mediated ribosomal 16S methylation in human bacterial pathogens.
    J. Mol. Biol. 359 : 358-364 (2006). [PMID: 16626740]

[EC created 2010]